A wheel cylinder for engaging a brake shoe according to which at least one piston is disposed in the bore of a body member and is adapted to move outwardly in response to a predetermined fluid pressure in the bore into engagement with a brake shoe.
|
5. A method of manufacturing a wheel cylinder that engages a brake shoe, the method comprising:
fabricating a housing having a bore;
fabricating a piston and a yoke from a single bar of material that is harder than the material forming the housing; and
disposing the piston and therefore the yoke in the bore so that the introduction of fluid into the bore moves the piston and the yoke in the bore.
1. A wheel cylinder for engaging a brake shoe, the cylinder comprising:
a housing having an inlet for receiving fluid and a bore in fluid communication with the inlet;
two pistons disposed in an axially spaced relation in the bore with each piston having a yoke formed integrally therewith and extending from one end of its corresponding piston outwardly from the housing;
the piston and the yoke being fabricated from a bar of material that is harder than the material forming the housing; and
a spring disposed in the space between the pistons with the ends of the spring being directly attached to the other ends of the pistons, respectively, for moving the pistons towards each other so that fluid introduced into the space between the pistons moves the pistons away from each other to engage the brake shoe.
3. The cylinder of
4. The cylinder of
6. The method of
7. The method of
8. The cylinder of
|
This invention relates to a wheel cylinder and, more particularly, to a wheel cylinder including a piston for actuating a drum-style brake for vehicles, such as automobiles.
Drum-style brakes for vehicles are well known and include a wheel cylinder usually having two hydraulically actuated pistons connected to corresponding brake shoes, which face the interior circumferential surface of the drum. The pistons respond to increases in hydraulic pressure caused by the actuation of the brake pedal and expand outwardly from the wheel cylinder body in opposite directions to displace the shoes outwardly into frictional contact with the brake drum. An arrangement of springs, or the like, is utilized to return the shoes, and therefore the pistons, to their original positions once the hydraulic pressure is reduced.
Typically the pistons and housing are fabricated from cast iron or other relatively soft material. Therefore, the portion of the pistons engaging the brake shoes must be fabricated from a stronger material, such as forged steel, which can withstand the forces from the brake shoe or a stronger component, usually in the form of an insert, has to be manufactured separately and assembled to each piston, which adds to the manufacturing and assembly labor and to the cost of the pistons. Another problem with these designs concerns the durability of the wheel cylinders. Typically, the wheel cylinder is located at a relatively low point in the vehicle. With the weight density of water being higher than that of brake fluid, water in the brake system will migrate, over time, toward the lowest point in the system where the wheel cylinders are located causing rust problems of the steel or iron components.
Although some more recent designs of wheel cylinders of this type include a body and/or piston of aluminum, these designs still require a separate insert of a different, stronger, material for engaging the brake shoe.
Referring to
The cylinder 10 responds to an increase in hydraulic pressure in a manner to be described and expands axially outwardly in opposite directions to displace the shoes 12 and 14 outwardly so that the shoes 12 and 14, and therefore the linings 12a and 14a, respectively, move into frictional contact with the brake drum to achieve braking action. It is also understood that an arrangement of springs, or the like, are provided to return the shoes 12 and 14 to their original positions once the hydraulic pressure is reduced. Since all of this is conventional it will not be described in further detail.
Referring to
Referring to
Two substantially U-shaped yokes 24a and 26a are formed at one end of the pistons 24 and 26, respectively, and are formed integrally with the pistons. The yokes 24a and 26a engage the brake shoes 12 and 14, respectively, with a tab (
The body member 16 is machined from cast iron or aluminum extrusion and the pistons 24 and 26, and therefore the yokes 24a and 26a, are formed of a relatively harder aluminum such as aluminum having the industry designation 6061T6 which is sufficiently hard to withstand the forces encountered when the yokes engage the above-mentioned members on the brake shoes 12 and 14, respectively. Each piston 24 and 26, including its corresponding yoke 24a and 26a, respectively, is manufactured by machining a single extruded aluminum bar to form the piston and the yoke. The dust boots 30 and 32 are made of rubber, or other flexible, resilient material.
As shown in
Two lip-seals 36 and 38 are disposed in corresponding circumferential grooves formed in the pistons 24 and 26, respectively, and engage the inner surface of the body member 16 defining its bore, in order to seal against the bore to prevent fluid ingress and egress.
The cylinder 10 is depicted in an inactive mode in
In operation, when the driver of the vehicle pushes on the brake pedal, additional hydraulic fluid is directed, via the port 18 and the passage 16a, into the bore of the body member 16. This increases the pressure of the fluid sufficiently to force the pistons 24 and 26 axially outwardly in opposite directions to the extended positions of
It can be appreciated that the one-piece pistons can be manufactured easily, do not require an insert of a separate material, and do not require any assembly. Moreover, each piston can be formed by extruding or forming one piece of aluminum and machining the aluminum. Machining the yoke on the end of each piston does not require any additional machining time since all necessary operations can be performed on a single machine, such as a multiple spindle screw machine or multiple station transfer machine. In addition to being relatively easy to manufacture, this eliminates other problems associated with the use of separate pistons and inserts, such as loose inserts, damage, or inserts not pressed to the proper depth.
It is understood that variations may be made in the foregoing without departing from the scope of the invention. For example, the invention is not limited to a wheel cylinder having two pistons, but rather a different number of pistons can be used. Also, although only one cylinder and one set of associated brake shoes for braking one wheel of a vehicle have been described, the embodiment disclosed above is equally applicable to every wheel of the vehicle. Also, the term “vehicle” has been used in its broadest since and is meant to include any type of wheeled device including, but not limited to, automobiles, airplanes, bicycles, and go-carts. Further, the yokes described above can be replaced with any other type of engagement member. Still the pistons, including their corresponding yokes can be manufactured by other, relatively hard material as long as the objects of the invention are achieved.
Although only one exemplary embodiment of this invention has been described in detail above, those skilled in the art will readily appreciate that many other modifications are possible without materially departing from the scope of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures.
Nguyen, Tien, Meagher, Michael P., Johnson, Art D.
Patent | Priority | Assignee | Title |
7325517, | Apr 29 2005 | IRIS ENGINES, INC | Radial impulse engine, pump, and compressor systems, and associated methods of operation |
7328672, | Apr 29 2005 | IRIS ENGINES, INC | Radial impulse engine, pump, and compressor systems, and associated methods of operation |
7392768, | Apr 29 2005 | IRIS ENGINES, INC | Radial impulse engine, pump, and compressor systems, and associated methods of operation |
7404381, | Apr 29 2005 | IRIS ENGINES, INC | Radial impulse engine, pump, and compressor systems, and associated methods of operation |
7650860, | Apr 29 2005 | IRIS ENGINES, INC | Engine with pivoting type piston |
7707975, | Apr 29 2005 | IRIS ENGINES, INC | Radial impulse engine, pump, and compressor systems, and associated methods of operation |
7753011, | Apr 29 2005 | IRIS ENGINES, INC | Radial impulse engine, pump, and compressor systems, and associated methods of operation |
7770546, | Apr 29 2005 | IRIS ENGINES, INC | Radial impulse engine, pump, and compressor systems, and associated methods of operation |
8100094, | Apr 29 2005 | IRIS Engines, Inc. | Radial impulse engine, pump, and compressor systems, and associated methods of operation |
Patent | Priority | Assignee | Title |
2140778, | |||
2212246, | |||
2938349, | |||
3478649, | |||
4742897, | Nov 29 1985 | Akebono Brake Industry Company, Ltd. | Wheel cylinder with self-contained auto-adjuster |
4896584, | Oct 22 1986 | Piston-cylinder assembly | |
5400879, | Dec 13 1993 | Robert Bosch Technology Corporation | Drum brake wheel cylinder with internal automatic adjustment |
5601345, | Dec 16 1994 | Kelsey-Hayes Company | Stationary seal ABS pump |
5870814, | Sep 29 1997 | Ralph D., Chabot | Method for replacing a vehicular wheel cylinder |
5882089, | Jul 10 1995 | Toyota Jidosha Kabushiki Kaisha | Hydraulic brake system for controlling fluid flow to a wheel cylinder |
6325181, | Jul 30 1999 | Kelsey-Hayes Company | Piston assembly for use in a wheel cylinder of a drum brake assembly |
6371257, | Nov 05 1999 | Kelsey-Hayes Company | Piston assembly for use in a wheel cylinder of a drum brake assembly |
Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
Nov 27 2002 | NGUYEN, TIEN | HILITE INTERNATIONAL, INC | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 013546 | /0725 | |
Nov 27 2002 | MEAGHER, MICHAEL P | HILITE INTERNATIONAL, INC | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 013546 | /0725 | |
Nov 27 2002 | JOHNSON, ART D | HILITE INTERNATIONAL, INC | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 013546 | /0725 | |
Dec 03 2002 | Hilite International, Inc. | (assignment on the face of the patent) | / | |||
Apr 08 2005 | HILITE INDUSTRIES-TEXAS, INC | NATIONAL CITY BANK, AS COLLATERAL AGENT | SECURITY INTEREST SEE DOCUMENT FOR DETAILS | 016470 | /0798 | |
Jul 25 2007 | National City Bank | HILITE INDUSTRIES-TEXAS, INC | RELEASE OF SECURITY INTEREST IN PATENT COLLATERAL AT REEL 016470 FRAME 0798 | 019605 | /0516 | |
Jul 25 2007 | HILITE INDUSTRIES-TEXAS, INC | BEAR STEARNS CORPORATE LENDING INC , AS COLLATERAL AGENT | FIRST LIEN INTELLECTUAL PROPERTY SECURITY AGREEMENT | 019781 | /0204 | |
Jul 25 2007 | HILITE INDUSTRIES-TEXAS, INC | BEAR STEARNS CORPORATE LENDING INC , AS COLLATERAL AGENT | SECOND LIEN INTELLECTUAL PROPERTY SECURITY AGREEMENT | 019795 | /0528 | |
Nov 05 2009 | HILITE INTERNATIONAL, INC | JPMORGAN CHASE BANK, N A | SECOND LIEN INTELLECTUAL PROPERTY SECURITY AGREEMENT | 023498 | /0378 | |
Nov 05 2009 | HILITE INDUSTRIES AUTOMOTIVE, LP | JPMORGAN CHASE BANK, N A | SECOND LIEN INTELLECTUAL PROPERTY SECURITY AGREEMENT | 023498 | /0378 | |
Nov 05 2009 | ACUTEX, INC | JPMORGAN CHASE BANK, N A | SECOND LIEN INTELLECTUAL PROPERTY SECURITY AGREEMENT | 023498 | /0378 | |
Nov 05 2009 | HILITE INTERNATIONAL, INC | JPMORGAN CHASE BANK, N A | FIRST LIEN INTELLECTUAL PROPERTY SECURITY AGREEMENT | 023498 | /0359 | |
Nov 05 2009 | BEAR STEARNS CORPORATE LENDING, INC | ACUTEX, INC | RELEASE OF SECURITY INTERESTS AT REEL FRAME 019781 0191, 019781 0204, AND 019783 0524 | 023486 | /0806 | |
Nov 05 2009 | BEAR STEARNS CORPORATE LENDING, INC | HILITE INDUSTRIES AUTOMOTIVE, LP | RELEASE OF SECURITY INTERESTS AT REEL FRAME 019781 0191, 019781 0204, AND 019783 0524 | 023486 | /0806 | |
Nov 05 2009 | BEAR STEARNS CORPORATE LENDING, INC | HILITE INTERNATIONAL, INC | RELEASE OF SECURITY INTERESTS AT REEL FRAME 019781 0191, 019781 0204, AND 019783 0524 | 023486 | /0806 | |
Nov 05 2009 | BEAR STEARNS CORPORATE LENDING, INC | HILITE INDUSTRIES-TEXAS, INC | RELEASE OF SECURITY INTERESTS AT REEL FRAME 019781 0191, 019781 0204, AND 019783 0524 | 023486 | /0806 | |
Nov 05 2009 | BEAR STEARNS CORPORATE LENDING, INC | HILITE INDUSTRIES AUTOMOTIVE, LP | RELEASE OF SECURITY INTEREST AT REEL FRAME 019795 0528 | 023486 | /0811 | |
Nov 05 2009 | BEAR STEARNS CORPORATE LENDING, INC | HILITE INTERNATIONAL, INC | RELEASE OF SECURITY INTEREST AT REEL FRAME 019795 0528 | 023486 | /0811 | |
Nov 05 2009 | BEAR STEARNS CORPORATE LENDING, INC | HILITE INDUSTRIES-TEXAS, INC | RELEASE OF SECURITY INTEREST AT REEL FRAME 019795 0528 | 023486 | /0811 | |
Nov 05 2009 | ACUTEX, INC | JPMORGAN CHASE BANK, N A | FIRST LIEN INTELLECTUAL PROPERTY SECURITY AGREEMENT | 023498 | /0359 | |
Nov 05 2009 | HILITE INDUSTRIES AUTOMOTIVE, LP | JPMORGAN CHASE BANK, N A | FIRST LIEN INTELLECTUAL PROPERTY SECURITY AGREEMENT | 023498 | /0359 | |
Jun 28 2011 | JPMORGAN CHASE BANK N A | Hydraulik-Ring GmbH | RELEASE OF SECURITY INTEREST IN PATENT COLLATERAL | 026553 | /0713 | |
Jun 28 2011 | JPMORGAN CHASE BANK N A | ACUTEX, INC | RELEASE OF SECURITY INTEREST IN PATENT COLLATERAL | 026553 | /0713 | |
Jun 28 2011 | JPMORGAN CHASE BANK N A | HILITE INDUSTRIES AUTOMOTIVE, LP | RELEASE OF SECURITY INTEREST IN PATENT COLLATERAL | 026553 | /0713 | |
Jun 28 2011 | JPMORGAN CHASE BANK N A | HILITE INTERNATIONAL INC | RELEASE OF SECURITY INTEREST IN PATENT COLLATERAL | 026553 | /0713 |
Date | Maintenance Fee Events |
Dec 01 2008 | M1551: Payment of Maintenance Fee, 4th Year, Large Entity. |
Nov 30 2012 | M1552: Payment of Maintenance Fee, 8th Year, Large Entity. |
Jan 06 2017 | REM: Maintenance Fee Reminder Mailed. |
May 31 2017 | EXP: Patent Expired for Failure to Pay Maintenance Fees. |
Date | Maintenance Schedule |
May 31 2008 | 4 years fee payment window open |
Dec 01 2008 | 6 months grace period start (w surcharge) |
May 31 2009 | patent expiry (for year 4) |
May 31 2011 | 2 years to revive unintentionally abandoned end. (for year 4) |
May 31 2012 | 8 years fee payment window open |
Dec 01 2012 | 6 months grace period start (w surcharge) |
May 31 2013 | patent expiry (for year 8) |
May 31 2015 | 2 years to revive unintentionally abandoned end. (for year 8) |
May 31 2016 | 12 years fee payment window open |
Dec 01 2016 | 6 months grace period start (w surcharge) |
May 31 2017 | patent expiry (for year 12) |
May 31 2019 | 2 years to revive unintentionally abandoned end. (for year 12) |